Yes but this would require 2 separate farms for wither boss. One for Nether seeds/soul sand and one for Wither seeds for the heads.
That is correct. The original post stated issue with excess material being accumulated and a want for something more efficient in that respect. Having two separate farms is the easiest way to manage the two resources without having an overflow of one or the other. Using JABBA Barrels or Storage Drawers ability to emit Redstone signal is a very easy trigger to avoid more cumbersome setups. I figured since he's playing a Skyblock, space isn't an issue (automated cobble/dirt/wood should be early priority) and by the time you're ready to auto-farm the Wither, your resource and power supplies should be a non-issue, so running a second farm would be a simple proposition.
A single farm pumping items into Storage Drawers or JABAA Barrels equipped with Void Upgrades is also an option to avoid overflow, but it didn't fit well with the efficiency request, as it will run full time wasting power and voiding half the drops.
Other options exist, of course, but figuring out the perfect ratios of crops (or how many growth accelerators to use for each crop type) ends up being harder and less predictable than just setting up the second farm.
